In fluid systems for aircraft, race cars, and in other applications where spillage of inflammable fuel or liquid may occur due to high impact forces being imposed upon the vehicle it is known to employ "crashworthy" couplings. Such couplings include frangible structure for interconnecting the valve bodies, and usually, the frangible structure is defined by weakened pins or portions utilized in the coupling interlocking components. In the event of a crash, high tension or bending forces applied to the coupling parts causes the weakened portions to fracture permitting the coupling halves to separate. Usually, each coupling half or part includes a self-sealing valve which is maintained in its open position when the coupling is in its normal operating mode. However, upon the coupling halves separating spring forces imposed upon the valves bias the valves to the closed condition preventing fluid flow and leakage from the associated conduit, such as a hose line.
While such crashworthy couplings have proven to be fairly dependable in operation, occasionally, a valve within a coupling part may lock, bind or corrode while in the open position and not rotate to its closed position in the event of a crash. Thus, there is a definite need to be able to test frangible couplings for fluid handling lines, but heretofore, such testing was not possible as the frangible interlocking structure for the coupling parts must be fractured before the coupling parts can be separated and the valve operation observed or tested. Previously, it was not possible to test a frangible coupling without destroying the interlocking structure.
It is an object of the invention to provide a frangible coupling for fluid systems utilizing at least one self-closing valve wherein the frangible interlocking means for the coupling parts may be operated to disengage the parts without damage thereto and the coupling parts may be reconnected to an operable condition.
A further object of invention is to provide a reconnectable frangible fluid system coupling wherein the coupling parts are interconnected by frangible components, and yet the parts may be selectably disconnected for testing purposes.
Yet another object of the invention is to provide a reconnectable frangible fluid coupling utilizing frangible interlocking apparatus for interconnecting the coupling parts wherein safety lock structure is employed in conjunction with the interlocking means to prevent inadvertent release thereof.
A fluid coupling in accord with the invention basically consists of two interconnectable parts each having a passage extending therethrough and each having an attachment end for communication with a fluid source such as a hose, conduit tank, or the like. In the most common embodiment the coupling consists of two parts each of which is attached to a hose end, and each part includes a self-sealing valve. In another version, only one of the parts may incorporate a self-sealing valve, and the coupling parts may be ridgedly mounted to a receptacle such as a fuel tank.
In the disclosed embodiments the passage of the valved coupling parts includes a rotary valve having a diametrical bore defined therein of a diameter substantially equal to the part passage diameter. Thus, when the valve bore is in alignment with the coupling part passage unrestricted flow through the coupling occurs. The rotary valve is associated with sealing seat structure as is well known and the valve rotates about a diametrical axis transversely disposed to the valve bore wherein a 90.degree. rotation of the valve is sufficient to move the valve between its fully opened and fully closed positions. A torsion spring biases the valve toward its closed position, and stop structure limits valve rotation between its operative positions.
The two parts of the coupling are interconnected by interlocking structure. Such interlocking structure takes the form of a circumferencial extension defined on one of the coupling parts which overlaps the other coupling part and is affixed there to. In the most common embodiment, the interlocking structure utilizes mating threads on the respective coupling parts to achieve interlocking.
The axially extending circumferencial interlocking extension defined upon one of the coupling parts includes weakened portions capable of fracturing in the event of high impact forces being applied to the coupling. These weakened frangible portions are of sufficient strength to maintain the coupling parts interconnected during normal operating conditions, but upon exceptional bending or tension forces being applied to the coupling parts the weakened portions, or webs, will fracture permitting the coupling parts to separate.
The valves, or valve, of the coupling parts is maintained in its opened condition due to engagement with restraining structure associated with the other coupling part, and upon separation of the coupling parts the restraining structure maintaining the valves in the open position is rendered inoperative permitting the valves to be quickly rotated by their associated biasing spring to the closed position to prevent fluid loss and leakage.
To prevent inadvertent release of the interlocking means a safety lock in the form of spring biased detent pins is employed. A plurality of detent pins are mounted in one of the coupling parts which cooperate with recesses defined in the interlocking structure of the other coupling part such that upon the coupling parts being fully interconnected the safety detent pins are received within recesses and the interlocking structure of the coupling parts cannot be released without positive and purposeful actuation of the safety lock detent pins by an operator.
The releasable aspects of the interlocking structure for interconnecting the parts of a frangible coupling permits the coupling to be tested to insure that the valves are operable and will rotate to the closed position in the event of impact and fracture of the webs. The construction of the invention produces no flow restriction through the coupling, and valve operation is substantially instantaneous to prevent spillage.